Death at UAH

As I was about to write up the latest smoggy stuff, I thought I’d better check out Eli in case he had written it up first. And lo, I thought, Condolences referred to the death of Christy’s scientific reputation. But no, it is about real death. So I need to press on.

[[John Christy]] has been a bit of a skeptic for ages. Quite where he gets it from is unclear – perhaps because he and Spencer did the first version of the [[satellite temperature record]] and, well, they got it wrong. In that it showed cooling, and so they became the poster boys for the real septics like Singer and Michaels and Inhofe. Perhaps some of that seeped in. But it turned out that a longer record showed a different answer, and that their version needed a pile of corrections, and when you do all that it shows warming. In the course of this long slow unravelling they got a fair amount of justified stick; and perhaps that pushed him towards the Dark Side.

But he was still a reputable scientist, somewhat in the mould of Lindzen though less eminent. Whilst clearly on the skeptical side he retained his k. The wiki page can’t really work out what to say about his views, which is correct, as it is hard to wade through the morass of conflicting stuff, and ends up with While he supports the AGU declaration and is convinced that human activities are one cause of the global warming that has been measured, Christy is “still a strong critic of scientists who make catastrophic predictions of huge increases in global temperatures and tremendous rises in sea levels.”

However, he got sucked in the the septic tide and published some stuff with Douglass in IJC in 2007 that was fundamentally flawed (Santer’s letter explains the details). The septics puffed it up; but it all fell apart a year later when Santer et al. ripped it to shreds, but of course there was a year of PR down the drain by then. Now Christy, I think, is not very strong on stats, and may well not have realised the error at the time of publication (though he should have known, because it had already been rejected from another journal for the same error). And a combination of pride, and of refusing to be corrected by the “other side”, and perhaps pressure from his co-authors, meant he never admitted to the error. Nor, as Santer points, did he ever attempt to defend it – defend in a proper scientific sense that is, not just in the sense of saying “we were right”. Instead he has a rather nasty piece which entirely evades the scientific issues (I don’t think their appendix A cuts it). They seem to complain that they never had a chance to respond to Santer’s paper which is odd – they had, and still have, every chance to write a proper response. Just like Santer et al. did. Instead, they chose to evade and whinge.

As Santer said, the paper that ended in IJC was intended for GRL. GRL is a far higher status journal, and has better quality reviewers, including Santer, and these reviews had already spotted the error. IJC is quite a lowly journal, and an odd choice for Americans, and looks like it was deliberately chosen as a journal of last resort for a dodgy paper. Christy relies rather heavily on selective quotes from leaked emails to make his case that the world is against him; it would be rather interesting were he to release the review comments on his paper.

100 thoughts on “Death at UAH”

Well, the timing is unfortunate but life goes on. IEHO there are two interesting questions here. The first is who approached whom. It really looks like Douglass started this and at some point Robert Knox was involved, so did they, ala Singer and Revelle, approach Christy for reputation? or visa versa? Did they approach Spencer or Lindzen first. Another reason to FOIA their emails, but alas, U Rochester is not a state university.

The second, well you will have to read Rabett Run tomorrow. Eli will think of something.

You point out that the paper was rejected from another journal as if resubmitting to another journal is unusual, but I don’t think that it is. Also I don’t think that an author is free to release reviewer’s comments.

[It is uncommon, but not unusual. It *is* a comment on the quality of the paper, as you are well ware. Christy seems to feel quite happy to print and discuss leaked emails, so why isn’t he happy to leak his reviewers comments? -W]

It actually wouldn’t be so easy to get another original article published on this topic, and the comment path in IJOC does seem closed off by the way this was done. To continue on the topic they would have to do much more than simply reply to what they perceive as the errors in the Santer paper.

[John Christy]] has been a bit of a skeptic for ages. Quite where he gets it from is unclear – perhaps because he and Spencer did the first version of the [[satellite temperature record]] and, well, they got it wrong.

Christy has talked about his experiences of being a southern baptist minister in Africa, and how that has helped shape his belief that the benefits of development to the third world far outweigh any possible climate change problems, and that such development will require fossil fuels.

It talks a lot about the intertwining of his experiences and beliefs, and his science.

It’s interesting because it was written before all the errors in Christy’s and Spencer’s work had been uncovered, so there are gems like:

As soon as he published his figures in 1990, Christy was attacked in scientific journals, in the media, and as the years passed, on the Web. There were questions about satellite drift, orbital decay, instrument temperature, and other possible biases. While environmentalists accused him of destroying the planet, industry public relations officers gleefully distributed Christy’s statistics on the Internet. Of the two contingents, Christy says, “I’m more upset with environmental advocacy groups who lie about my data, who say it’s inaccurate.”

Well, it wasn’t just environmental advocacy groups, and they weren’t lying, Christy and Spencer were wrong.

Later in the article:

To keep politics from appearing to bias his science, Christy refuses support from industry groups. He works strictly with funding from NASA, the National Oceanic and Atmospheric Administration, the Department of Energy, the Department of Transportation, and the state of Alabama. But he is driven by a fundamental, religious belief that human life is “precious above all else,” and his doubts about global warming can almost seem like an outgrowth of his distaste for any centralized government action. Asked what he would do if his data did show the troposphere warming in lockstep with the Earth’s surface, he seemed genuinely at a loss. “I guess I’d still be skeptical about forecasts of catastrophe,” he said. “That’s my nature.”

You should also look at Christy’s role in the dreadful Klotzbach et al 2009 in JGR.

Question #1:
How did he not catch that it was not reasonable to assume that modeled (or real) tropospheric amplification factor, relative to surface temperature trends, would be identical over land and ocean?

That’s a major error in his field of expertise, is it not?

[He is 4th author behind the Pielkes. It isn’t good, but he probably didn’t do much for it. His major area is radiative transfer (I think) and while he has been around this stuff a lot, he may not be so great at land-sea basic climatology stuff. I’m not close enough to know -W]

William politely neglects to recount the remainder of Christy’s history of dodgy papers, denialist-leaning public pronouncements, bad behavior when working with peers and association with anti-scientific wingnut enterprises like the George Marshall Institute. It’s quite the rap sheet.

I agree with dhogaza that the likely explanation for Christy and the handful of similarly-situated scientists is that they simply refuse to believe that reality would do this to them, regardless of whether those views are based on what they think jeebus says or just plain personal incredulity. Per Planck, there’s just no convincing such people.

Re #2, if Christy and colleagues had any sort of legitmate refutation of Santer’s critique they would have no problem getting it published somewhere. Even if Christy’s reputation has gotten so bad that he can’t find a publisher, and arguably it has gotten that bad, there’s nothing keeping him from doing the work and putting it up on arXiv.

IMHO the scientific community needs to come up with a method of dealing with the likes of Christy. He needs to be delegitimized such that people like Andy Revkin can no longer justify quoting him. OTOH Revkin still uses Pat Michaels as a source, so go figure.

Last March, more than 100 past lead authors of report chapters met in Hawaii to chart next steps for the panelâs inquiries. One presenter there was John R. Christy, a climatologist at the University of Alabama, Huntsville, who has focused on using satellites to chart global temperatures. He was a lead author of a section of the third climate report, in 2001, but is best known these days as a critic of the more heated warnings that climate is already unraveling under the buildup of heat-trapping gases.

At the Hawaii meeting, he gave a presentation proposing that future reports contain a section providing the views of credentialed scientists publishing in the peer-reviewed literature whose views on particular points differ from the consensus. He provided both his poster and summary of his three-minute talk. In an e-mail message to me, he described the reaction this way (L.A. is short for lead author; AR5 is shorthand for the next report, coming in 2013-14.):

The reception to my comments was especially cold â¦ not one supporter, though a couple of scientists did say I had a âlot of gutsâ to stand up and say what I said before 140 L.A.s. I was (and still am) calling for the AR5 to be a more open scientific assessment in which those of us who are well-credentialed and have evidence for low climate sensitivity (observational and theoretical) be given room to explain this. We should have the same standards of review authority too. When a subject is excruciatingly complicated, like climate, we see that opinion, overstatement, and appeal-to-authority tend to reign as those of a like-mind essentially take control in their self-constructed echo-chamber. The world needs to see all sides of the evidence. We in the climate business need to understand humility, not pride, when looking at a million degrees-of-freedom problem. Itâs just fine to say, âWe donât know,â when that is the truth of the matter.

I also asked him, âDo you see a way forward for this enterprise (presuming you see these recent issues as serious problems but not a fatal indictment)?â He said:

I think people would read AR5 if it were a true scientific assessment, complete with controversies [described] by the experts themselves. Policymakers will find it uncomfortable, because the simple fact remains that our ignorance of the climate system is enormous. Otherwise, it will be a repeat of what we are now seeing (and what many folks like me knew years ago), that the process has morphed into an agenda-approving exercise.

Seems like they jump the shark at some point, where they shift to primarily speaking to a non-academic audience.

I think it was when the UAH product finally started resembling reality, and they no longer had that to back up their naysaying, and when Christy as part of the NAS/NRC committee put together by the Bush administration signed on to the unanimous statement that the surface station temps were as accurate as the satellite reconstructions. He began backpedaling from that almost immediately afterwards.

Steve Bloom:

So essentially he’s saying AR5 should be required to include crap.

This is interesting, though:

We in the climate business need to understand humility, not pride

Well, with the errors he and spencer made with the UAH satellite temp product, you’d think he’d show a bit more humility.

That didn’t seem offhand like a bad article, but it certainly establishes they were working with the GMI folks very early. It does already start worrying surface records,l UHI, etc … but of course, some of that could be and unsurprising wish to to push satellites (OK).

Christy has published research papers looking at these effects in three different regions: east Africa, and the American states of California and Alabama.

âThe story is the same for each one,â he said. âThe popular data sets show a lot of warming but the apparent temperature rise was actually caused by local factors affecting the weather stations, such as land development.â

I’ve only read the abstracts. They show evidence of land surface effects on temperature trends. They don’t come near to showing that all or most global temperature change over the land is due to land surface effects.

Aye, that Times article is a terrible piece of work, suggesting that the Times wants to become a tabloid.
We have an out and out lie from Christy, filler writing carefully slanted to cast doubt on the warming bit, McKitrick who as far as I can tell was an anti-AGW hack long before he wrote his paper, and anyway what he says is wrong. Then we have Watts et al’s non-peer reviewed rubbish which is swallowed wholesale. Then we have Terry Mills. Anyone seen his paper? The stuff quoted was so outlandishly wrong that I e-mailed him to ask about the paper in question, and now have a copy of it, but its in statistics so I don’t understand it. Either way the sentence quoted is misleading in the context of the article, and anyway statistics are irrelevant to the physical reality of pumping billions of tonnes of CO2 into the atmosphere.

[Mills may be genuine, indeed quite likely is, but is probably doing the std statistician coming in to sort out these climate types and getting hopelessly confused -W]

I just read their Appendix A. Would have liked to read Santer’s too, but his is not included in the pdf.

I never followed this in great detail, but what’s wrong with their argument? They are looking at the relationship between model surface and atmospheric trends. It is quite conceivable for the *trends* to be all over the place, but for the *relationship* to be in lock step, and hence have much smaller error bars.

Trivial example: someone gives you model surface temps in C and F, but doesn’t tell you what they are. Different models (and different runs within the same model) will have widely varying series, but the relationship between the C and F series for each model will have zero variance.

Thanks to William for this thread and to dhogaza for pointing me to it. I had just posted today at Open Mind wondering if Christy was a skeptic due to religious beliefs but now I see that is just one facet.

#28: “DCPS ignore the impact of interannual variability in both the observed and modelled trends.”

Yes, to which Christy has responded (in summary): “we’re not modelling interannual variability, we’re modelling the relationship between surface and tropospheric trends”

If I understand the argument (and since Santer does not provide his “Appendix A” I can’t verify), Santer would take two measurements of the same series, one in C, and one in F and say that any measurement of the relationship between C and F must have variance at least as great as the variance in the individual series themselves. Which is clearly false (F = 9 / 5 * C + 32 – no error bars at all). Obviously this is an extreme example, but it makes the point that Christy is making: the relationship between two random variables can be a lot more predictable than the variables themselves.

But I could be wrong. This is really simple stuff so I can’t imagine that Santer would have missed such a trivial point, or that it would form the justification for the evisceration Christy is receiving.

The point is that you cannot assume that there is zero error in the observational record. The total variance is the root mean square of the sum of the squared variances of BOTH observation AND modeling (actually Eli has a whole lot of other issues about DCetc.)

What Santer+17 say is the best way of handling the situation is to compare all the models to all the observation series pairwise (since on the one hand, they can be modeling slightly different things,and on the other they can be measuring slightly different things and in a case like that it is not clear what simple averaging buys you). When they do this there are very few pairs which are inconsistent. This is an elegant way of handling the question. OTOH, they cay use DGetc’s way, and if they do it correctly, accounting for variance on both sides, hey, it still comes out that models and observations are consistent.

Thanks for the link. This is definitely worth looking into further given that a good fraction of the entire [insert collective noun for leading pro-harmful-AGW climate scientists] weighed in on the issue.

However a quick skim of the Appendix did already yield a chuckle. In their answer to Question 9 they point out that the DCPS test yields a positive result even when fed with random noise, and that this is a bad thing (which it probably is but I need to know exactly what they did). Does anyone remember this level of honesty when McIntyre demonstrated that Mann’s algorithm finds hockeysticks in red noise? Me neither.

[This is a common misunderstanding, which M&M have pushed as hard as they can to make as many people as possible misunderstand, but it is wrong -W]

Don’t worry Eli, I will “RTFP” when I get time. But these things take time, especially when the main purpose of the paper is to support a preconceived position and debunk a political opponent, for then you can’t take anything the authors say on face value (any “explanatory note” with 17 authors is political. These are not experimental particle physics papers).

Hank, the papers you link to are almost unreadable. So many cross references, no simple statement of problem or solution, and again, in this case, we know the purpose is to defend a preconceived viewpoint so you can’t trust anything (that’s not to say any claim they make is false, just that to get to the bottom of things you have to follow every trail and verify it for yourself. Simply too much work). BTW, I found one reference to “red noise” in the first paper on that page, with criticism that I couldn’t follow without more work, and zero references to Yamal.

And using lack of publication from skeptics as evidence against their position doesn’t really carry much weight post-climategate, given that we now know there were (and presumably still are) coordinated efforts to prevent publication.

Remember, it’s easy to cite, it’s a lot harder to really understand. 9/10 times someone cites a climate paper at me they haven’t really understood what’s in it (Roe and Baker for a recent example).

Jonathan Baxter on the one hand is stating that he has neither the scientific nor the statistical knowledge needed to evaluate any of the claims, and on the other is doing so. There is a name for that and he deserves large amounts of derision.

The funny thing is we now know (from climategate) that many in the climate science community (Tom Wigley included) believe the hockeystick reconstructions to be dubious. That, along with the declarative — rather than explanatory — style, is what makes reading Wahl and Ammann difficult: you have to read it for what you’re not being told.

“Phil,
I have just read the M&M stuff critcizing MBH. A lot of it seems valid to me.
At the very least MBH is a very sloppy piece of work — an opinion I have held
for some time.
Presumably what you have done with Keith is better? — or is it?
I get asked about this a lot. Can you give me a brief heads up? Mike is too
deep into this to be helpful.
Tom.”

“Jonathan Baxter on the one hand is stating that he has neither the scientific nor the statistical knowledge needed to evaluate any of the claims”

Where did I state that Eli? I have both the scientific and statistical knowledge, but not the stomach, for Wahl and Ammann. Santer is much easier, and that is what I claimed to have on my reading list.

I note that your last scientific argument (as opposed to citations or political remarks) was bunk (objections to Roe and Baker are merely formalistic because we’re far from the pole). Maybe you should get your own house in order before directing derision towards others?

@Jonathan Baxter:
Wahl and Amman tested whether reconstruction using other statistical methods changes the shape of the reconstruction. It didn’t, thus the title of the article. Is it a “preconceived viewpoint”? No, there was no prejudice without evidence, as there *was* evidence* (several others getting similar reconstructions). Your choice of words is getting into the grey zone of “plausibly deniable accusations”.

Oh, and the mail you cite does not claim the reconstruction is “dubious”, but it uses the word “sloppy”. Those are not synonyms.

JB, I’d be willing to concede you a modicum amount of credibility, and maybe even to believe your claim of scientific and statistical competence, had you given any indication that you haven’t simply swallowed every bit of crap produced by M&M and their ilk. IOW, they’re running a shell game and you’re just a rube. Here’s a hint: The global average climate of the last 2K years is simultaneously fascinating and not at all central to the main conclusions of climate science. But by all means don’t let me stop you from keeping your focus firmly on the shells without the pea.

@Marco: come on, there’s only three possibilities: 1) W&A were entirely disinterested and pursued their line of research out of pure academic curiosity; 2) they were convinced by McIntyre’s arguments but surprisingly found them to be without merit; or 3) they set out to buttress Mann’s approach.

2) is out of the question. Before climategate I might have lent towards 1), but not now. There’s too much hard evidence of coordinate attacks on any prominent skeptical work. So that leaves 3).

As for “dubious” vs “sloppy”: you’re a finer linguist than I. IMO “dubious” is more charitable than Wigley’s full statement: “At the very least MBH is a very sloppy piece of work”.

Also, the closing of ranks behind Mann and the failure to publicly voice the kind of private concerns expressed in Tom Wigley’s email doesn’t instill one with great confidence.

Uh, the W&A paper is a public voicing that M&M’s narrow concern was correct but didn’t change the basic conclusions of the paper.

Got it?

A) it is strong evidence that the climate exhibits greater natural variability than is currently understood, and B) today’s warming could, at least in part, be attributable to such internal variability.

Neither of these is true. It would simply tell us that the MWA was something that current evidence suggests it isn’t, i.e. a global, synchronous event. A) tells us why the denialsphere is so focused on the MWA, nothing more.

B) no, it wouldn’t. It would tell us that some forcing we don’t have good measurements for (it being a long time ago and all that) was higher than thought. It might make us think that solar output reconstructions for the time period are off, for instance. But it wouldn’t tell us that attribution of current change is wrong.

@Jonathan Baxter:
Wow, you do babble a bit about my dubious vs sloppy, but completely neglect the issue with “preconceived”. Once again: the evidence was there that the MBH98 reconstruction was not nearly as bad as claimed by ‘certain individuals’. They thus tested the null hypothesis. Nothing “preconceived” there. In fact, “preconceived” even suggests data manipulation (either directly or by omission). Unless you can show anything fundamentally wrong with W&A, your handwaving dismissal of their results is outright laughable.

Oh I get it, you think the fact that your query generated 135 hits means I am somehow in bed with Christy. Too funny. I’ve never met nor corresponded with the guy. But some of those hits are seriously incriminating (sarcasm alert), eg:

They included me under the “outreach to industry” section because I was still supervising PhD students there even though I had moved to the US. Hilarious – I’d never seen that. Bureaucrats maximizing metrics.

dhogaza, forcing could be an explanation, but so could internal variability. I expect forcing is a lot less likely an explanation, since we have a pretty good handle on that pre-industrial times. But anyway, I doubt you’ll find disagreement with those options from amongst reputable climate scientists.

How long is this larger globalised MWP supposed to have lasted?
Its not obvious that the the estimated natural variability would have to be raised
(a) Keep the forcing in the pre-industrial phase the same.
(b) Asume that aerosols have been under-estimated in the blade of the hockey stick.
(c) Boost the estimate for the climate sensitivity above the lowish values given in Mann and Kump’s Dire Predictions page 81 (i.e. 2-3 degs. C per 2 X CO2) for the hockey stick. That would make McIntyre more dire than Mann and Kump.

RE #55: See my comment at #52. What’s are more likely explanation for MWP: huge sensitivity or natural variability? The required sensitivity would be inconsistent with the temperature difference between now and the LGM. And the time scale seems reasonable for natural variability: the ocean takes 1,000 years to turn over so it is not out of the question that heat could be pumped from ocean to atmosphere or vice-versa on a centennial scale.

So you’re an IT guy and entrepreneur in data mining?
Commendable. Relevant to climatology, not too clear.
You don’t read the science papers, but you opine extensively and widely on them. “That must be … lucrative.”

My background is statistical machine learning. It’s relevant to robustness claims in climate and modeling. I majored in pure math/theoretical physics, so I can at least understand the physics.

RE #55: I read the realclimate post. The rat/spring analogy a priori excludes natural variability, so can’t be used to argue against Esper. To model natural variability the platform has to raise and lower without interference from rats.

We know the climate can change substantially on decadal scales without forcing (look at the 20th century). Why not centennial scales? We don’t have the temperature records to prove it, but it seems almost certain that the time constants in climate are large enough to allow for it.

In other words, your sky fairies are more likely than established physics.

“Established Physics” says a physical system with centennial-plus time-constants will almost certainly exhibit centennial-plus oscillations in *some* observed quantity. Since the big time constants are in ocean behavior, and the oceans move heat around the system, it is reasonable to assume the temperature will exhibit centennial-plus oscillations.

But if you don’t like my intuition, google is (as always) your friend:

@Paul Kelly: please provide a link to the Kerry Emanuel article putting climate sensitivity to 1C. Would be interesting, considering that climate sensitivity isn’t his expertise.
Now, if you are claiming this piece:http://www.boston.com/bostonglobe/editorial_opinion/oped/articles/2010/02/15/climate_changes_are_proven_fact/
supports your claim, you may actually try and understand his disclaimer “in the absence of any feedbacks except for temperature itself, doubling carbon dioxide would increase the global average surface temperature by about 1.8 F”.

JB: “Since the big time constants are in ocean behavior, and the oceans move heat around the system, it is reasonable to assume the temperature will exhibit centennial-plus oscillations.”

*sigh* To the extent that we assume such a thing, it’s an argument for regional variability. Global variability would be unphysical to the point of ludicrousness. Try thinking about what would have to be happening for it to be true.

Oh, BTW, I suspect Our Host would be joining in on the fun if [redacted]

[Um. Please keep this polite. Every now and again I’ll stomp on someone who crosses my imaginary line. I think this discussion has probably gone as far as it usefully can -W]

“Established Physics” says a physical system with centennial-plus time-constants will almost certainly exhibit centennial-plus oscillations in *some* observed quantity. Since the big time constants are in ocean behavior, and the oceans move heat around the system, it is reasonable to assume the temperature will exhibit centennial-plus oscillations.

(for the less idiotic than this poster, it’s not necessary to “assume” centennial-plus oscillations when 1) there’s no evidence that they exist (so stated by the poster, earlier) and 2) physics is able to explain what’s going on)

Meanwhile, when did the sky fairies stop beating the women in your family on a centennial-plus basis without leaving a bruise?

I am not sure what definition is being used for natural variability.
(a) Unforced variability
(b) Extremist contrarian variability i.e the natural variability which would occur in an imaginary world in which the variation of the greenhouse gases is ignored.

In type (a) you would get e.g.:

small natural variation of T > more water vapour and clouds > bigger natural variation of T

The magnitude of this effect increases with climate sensitivity.

Not in type (b) but that applies to an imaginary world in which the physics of water vapour warming has been disproved.

RE Steve Bloom #64: “*sigh* To the extent that we assume such a thing, it’s an argument for regional variability. Global variability would be unphysical to the point of ludicrousness.”

No. Two things:

1) global variability is known to occur on decadal time scales. If it is “unphysical to the point of ludicrousness” on a centennial scale then it would at least be “unphysical to the point of dubiousness” on a decadal scale.

2) The oceans are a “region” in the sense required by physics. Heat from the atmosphere can go into the ocean and vice-versa. In fact, this is one of the arguments (put forward by Wigley from memory) against the significance of the recent lack of *global* warming: all the heat is going into the oceans.

@Paul Kelly:
Climate sensitivity without any feedbacks to 2xCO2 has been determined to be 1C for ages. Emanuel thus did not remove anything, contrary to your claim. The 1-5C extra comes from the feedbacks that are known to occur, but where there is more uncertainty.

RE #67: a). But it’s not really “unforced” variability. The heat is coming from somewhere – for the sake of argument assume the oceans.

So:

dT = dF * S

where dT is the change in temperature (K), dF is the change in forcing (W/m2), and S is the sensitivity (K/W/m2 – feedbacks included).

Now assume there are only two independent sources of forcing: ocean heat and CO2 (there are more but for our purposes they can either be lumped with the oceans (anything not caused by humans) or CO2 (anything we can potentially control, like CO2, land use, etc).

So:

dF = dF_ocean + dF_CO2

or dT = ( dF_ocean + dF_CO2 ) * S …. (1)

We want to solve for S. We can measure dT and dF_CO2, but dF_ocean is unknown.

Assume dF_CO2(MWP) = 0 (ie – forcing due to CO2 was constant pre-industrial times, so the change in forcing due to CO2 in the MWP was zero). So from Equation (1):

dT(MWP) = ( dF_ocean(MWP) + 0 ) * S

or

dF_ocean(MWP) = dT(MWP) / S

Given that dF_ocean is “internal”, some portion of it could be happening today. So dF_ocean(2010) = k * dF_ocean(MWP) for some unknown constant k. So from Equation (1) for today:

dT(2010) = ( dF_ocean(2010) + dF_CO2(2010) ) * S

or

dT(2010) = ( k * dF_ocean(MWP) + dF_CO2(2010) ) * S

or

dT(2010) = ( k * dT(MWP) / S + dF_CO2(2010) ) * S

or

dT(2010) = k * dT(MWP) + dF_CO2(2010) * S

Solving for S we get:

S = ( dT(2010) – k * dT(MWP) ) / dF_CO2(2010)

The no-feedback contribution from CO2 is about 1.5 W/m2 (390ppm vs 280ppm). But there are forcing filters that apply today and not at the MWP (eg aerosols) so dF_CO2(2010) = 1.5 / G where G > 1. dT(2010) is about 1C. So:

S = 2/3 * G * ( 1 – k * dT(MWP) ) … (2)

The point of all this? Equation (2) shows the climate sensitivity is a *decreasing* function of the MWP temperature if k > 0.

[No. All else being equal, the larger the MWP variations were, the more sensitive the climate is. Obviously -W]

RE 77. Not really. There’s no question it has gotten a little warmer. There’s no question some of the temperature rise is due to GHGs. But those plots can’t distinguish trend from a long cycle. If we had data back 1,000 – 2,000 years we’d have a better idea. Even then, we’d need a lot more than just Maine.

RE #79. Well, yes. We’ve come full circle. Mann used all that to do his multi-proxy studies, in the process claiming to have wiped out the MWP. Finessing the question of how robust his conclusions are (not at all IMO, but I better leave that alone because William will nuke this comment if I don’t), the “modern” response expressed here and elsewhere is “it doesn’t matter anyway because a *warmer* MWP implies *higher* sensitivity”. But my calculation in #70 shows that reasoning is faulty.

Letâs assume these studies somehow greatly underestimated natural variability in the climate system, so that the âsignalâ of anthropogenic climate change has not yet emerged from the ânoiseâ of natural variations.

Then “it doesn’t make any difference”:

A new large uncertainty analysis that appeared this week in Nature shows that it is very difficult to get a climate sensitivity below 2 ÂºC in a climate model, no matter how one changes the parameters.

If there is large natural variability that is not manifested by the climate models, how can he draw strong conclusions about those models?

With few exceptions, this is always how it goes. Some argument that superficially looks convincing but doesn’t hold up under closer scrutiny. Fundamentally, these guys just *know* sensitivity is high.

“Previously published work using satellite observations of the clear sky infrared emitted radiation by the Earth in 1970, 1997 and in 2003 showed the appearance of changes in the outgoing spectrum, which agreed with those expected from known changes in the concentrations of well-mixed greenhouse gases over this period. Thus, the greenhouse forcing of the Earth has been observed to change in response to these concentration changes. In the present work, this analysis is being extended to 2006 using the TES instrument on the AURA spacecraft.”

RE #90: Where is the calculation or measurement of dT / dF at the LGM? Some groups have tried to *model* it, but the whole point of the LGM argument is that it is meant to be an independent verification of the models.

This causes what used to be PC#4 to become PC#1. It does not cause old PC#4 approx new PC#1 to become âhockey-stickâ shaped; it already was. It doesnât make old PC#4 approx new PC#1 strong enough to be called âsignificantâ in the sense that itâs demonstrably more than just noise; it already was. It certainly doesnât make old PC#4 approx new PC#1 correlate with temperature during the calibration and verification intervals; it already did.

And then read the rest of the analysis. Its far more complete than the unfinished works of McIntyre and Wegman (who just makes ex-cathedra statements) and shorter than the more thorough sources whose length you complained about.

The original thread was supposed to be about Christy (not Spencer) so I shall resist the temptation to continue the diversion into a discussion of re-defined forcings and sensitivities.

then press your PageDown button repeatedly until you locate the information you need in that paper.

Note that this is not the only or best answer; this is one example of how to begin looking this kind of thing up.

Follow the references and use keywords that you find from your first search to improve on it. Use Scholar as well.

You no doubt know how to look this stuff up for yourself.

I give the long answer for youngsters who may come along later, read your faux-naive post and be fooled into thinking well, gee, if this rich old software entrepreneur dude with all the publications can’t find this dt/df stuff, it’s probably really not there to be found.

“I give the long answer for youngsters who may come along later, read your faux-naive post and be fooled into thinking well, gee, if this rich old software entrepreneur dude with all the publications can’t find this dt/df stuff, it’s probably really not there to be found.”

Unfortunately for you Hank, those “youngsters” would be correct (except for the “old” part – unless 43 is old. oh and the “rich” part too, unless you have a buyer you’d like to introduce me to).

I asked for “dT/dF at the LGM” not “DT/DF between the LGM and now”. The first is a derivative and is only equal to the second under the assumption that the climate sensitivity has been (more-or-less) constant between the LGM and today.

So I read through your links summarizing the controversy between Christy and Santer. Santer’s letter doesn’t seem to address the points being raised very well. Was he a reviewer for GRL of Christy’s paper? Having Santer rejecting a paper that criticized Christy is different for having an independent reviewer do so. Santer says his paper should be treated as an independent submission, and not a reply to Christy, but reading the leaked e-mails it certainly looks like they were trying to ensure they get the last word on the subject. Santer’s letter doesn’t address the points made in Climatology Conspiracy.

@MikeN:
Santer admits to being reviewer for the original submission to GRL. Note that that paper did not include Christy.
Santer also apparently wanted his paper to appear in the same issue as the new Douglass et al paper. That’s all.

Of course, I doubt you really understand what Santer is saying, considering you claim he does not address the points. He does. For starters, he shows that his paper had about the same time-from-submission-to-acceptance as Douglass et al (a few days shorter). This already strikes down one of the lies of Douglass and Christy.
A second issue is Douglass and Christy’s claim that the publication was stalled. This is another lie: it was available online as a publication ahead of print for many months!
A third issue is the claim that the IJoC paper was essentially the same as the GRL submission. Santer has seen both, and thus knows this to be false. In addition, they even exchanged an author. If it really was the same, Christy’s addition as a co-author (and removal of Knox) is actually very questionable scientific behavior. Etc. Etc. Etc.